Painting over weatherproofed wood

Hello Everyone

I am new to the site and am looking for some advice on painting over external wood which has been weatherproofed.

We have recently moved in a bungalow which has a half wood porch, the wood has been coated with a weatherproof application - it could be creosote and was dark brown although it now needs improving. Does anyone know if I can cover this with an external gloss paint or any light colour application I can use. Any advice would be greatly appreciated.